Engine running hot.

[Todd 1669]

I have a 1978 Evinrude 55hp that seems to be running a bit hot. After 15-20 minutes of WOT I took the cover off and the top of the flywheel was pretty hot. Hot as in my hand could only rest on it for a few seconds. Putting my hand on the head it was hot to the point I looked for burns after a second. I dont remember this much heat coming off of this motor before. Its peeing water fine. Im ordering a impelller today but is there anything else I willl need to replace or look at?
Thanks again to all helping members.

 

[gsyfishy]

Re: Engine running hot.

Check the Themostat< if its bad, it will not open up at the correct temp, this limits water flow.

 

[Todd 1669]

Re: Engine running hot.

I looked for a while but couldnt find a thermostat on this motor. Also looked through the manual and online at parts listing. Still no thermostat information. The pee tube comes out of the exhaust cover. Is the thermostat under there?
Posted this a minute too early. I found it being listed under the cylinder head cover.
Can this be tested or is replacement a better option.

 

[rusirius]

Re: Engine running hot.

You can test it by putting it in water and making sure it opens at the right temp... In other words... Put a pot of water on the stove with a thermometer... Watch when the temp gets to the "open" temp (i.e. 143 degrees) and make sure it opens... Make sure you get a new gasket for the head cover too...

 

[Lino]

Re: Engine running hot.

I looked for a while but couldnt find a thermostat on this motor. Also looked through the manual and online at parts listing. Still no thermostat information. The pee tube comes out of the exhaust cover. Is the thermostat under there?
Posted this a minute too early. I found it being listed under the cylinder head cover.
Can this be tested or is replacement a better option.

Yes you can test a thermostat if you have a thermometer that is accurate and can handle the temperature.
Heat some water on the stove with the thermostat in and a thermometer in a pan and see if it opens.
It should be fully open at 190 to boil depending on the opening temp.
They do stick but can be cleaned and that might help, but once it sticks there is a chance of it sticking again, should be cheap insurance to buy a new one if yours is sticking.

 

[Todd 1669]

Re: Engine running hot.

Took the thermostat out and tested it on the stove. After a couple of tests it looks like it opens at approx 160 degrees. I put it back in. There wasnt a gasket between the head cover and the head so I ordered a new one as well as a impeller. I will run it again and try a more scientific approach to checking the temp. The day the motor seemed warm the outside temp was 85 deg. It was the first warm day of the year and possibly made it seem like the motor was running hotter.

 

[kenmyfam]

Re: Engine running hot.

Tell tale will only tell you that water is flowing and not how much.
Change impeller and make sure the pump housing and related parts are in good shape. I will check on thermostat and post back.

 

[kenmyfam]

Re: Engine running hot.

Looking at the parts list you do have a thermostat.
Part # 0378065
Follow this link

http://shop2.evinrude.com/ext/index.aspx?s1=bf6ad09c53cead335fcfd8a6471c0f7f

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